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Syncrowave 180 SD stuck on max current

03-05-2011, 06:41 PM

I'd appreciate some advice with resolving the following problem with my Syncrowave 180 SD - After being stored for the past 4 months in the garage I started the welder up today and to my surprise it seems to be stuck on max power using both stick and TIG. Striking an arc results in a hole blown in the metal ( a big surprise in TIG!); switching the polarity, current dial changes, etc. do not solve the problem.

The welder is 10 yrs old, used for small projects and probably has no more than 15 hrs of running time on it. There were some cob webs inside the welder case but nothing obviously wrong. I'm totally stumped!! How could the welder go bad just sitting!?

I would open the cover, and look at the potentiometer, which is connected to the amp knob. If you have an ohmmeter, turn the knob and watch the values change. Look for any kind of short or bad connection.

Sometimes things are really obvious when you look, worth taking the time to look. Maybe you will see parts on the control board that have had the smoke let out.

Richard

Syncrowave 200, Millermatic 211, Victor torch, Propane forge....

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While you have the covers off, remove the connectors from the control board and apply some dielectric grease such as Super Lube synthetic grease to them and re-insert. Also, if I remember correctly, on the left side is the current sensor, which also has a connector on it (4 pin, I think). Unplug it and do the same thing with the grease. The sensor has a large copper bar running through it. If the problem persists after doing this, it is likey a bad current sensor. If that is the case, you can get one from Miller (very expensive) or from Digi-Key Electronics for about 1/3 the cost. Feel free to PM me if you need a sensor, and I'll try to find my records from when I ordered one.

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What GerryR said. The output current sensor sends a very low voltage signal to the control board so even a slight corrosion at the 4-pin connector can be the cause of the problem. Same would hold true for other control board inputs.

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Many thanks for the excellent advice! I put dialectric grease on all connections to the board and the 4 pin connection to the current sensor, although they all looked in real clean condition. Unfortunetly the problem continues so I will order the replacement current sensor part # 191941 in the hopes the issue is with the sensor. I will also update this thread once I have the new part installed.

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I've got a similar problem with a 180 SD, only this one is sort of intermittent.

Same deal, full current regardless of control or pedal settings. Took the cover off, cleaned off the connector pins on the current sensor, reassembled. Worked fine for an hour or two. Next week, same problem, same fix, then problem returned.

Then talked to Miller, ordered a current sense device, installed, worked fine for a couple hours. Next week, same problem, fixed for an hour after I opened it up and re-plugged the sensor wires. Miller guy had told me that sometimes position of sensor wires could cause trouble, so I taped them as far away from the big wires as I could. Again, fixed for an hour, but last time I jiggled the wires, no luck, so the thing is basically dead at this point.

Any thoughts? Should I assume there is a problem with the board? The wiring? You know those intermittent problems can drive a person crazy! If anyone knows a repair shop in the Chicago area that might be of help, please let me know.

--Buckapound

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Same with me, intermittent. Would unplug and replug and it would work for a while. Now, it's back to before, with no control. I posted the identical problem so but I'll join you with searching for a root cause. I haven't bought a replacement hall sensor yet. Thanks

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Just a thought,
Check for loose/displaced pins/sleeves in the connector(s) or cracks in the circuit board traces -might occur close to the connector mounting. Use a good big magnifier. Doesn't seem to be a common cause but you never know..
Meltedmetal